1. Technical Field of the Invention
The present invention relates to the field of semiconductor packages and their fabrication.
2. Description of Related Art
A known semiconductor package comprises perforated flat metal leadframe having a central platform and radiating electrical connection leads distributed around and at a certain distance from this platform. An integrated circuit chip is bonded to the front face of the platform. Electrical connection wires connect front contact pads on the chip to the front face of the electrical connection leads. A block of encapsulating material encapsulates the chip and the electrical connection wires on the front of the leadframe and fills the spaces that separate the platform from the electrical connection leads and the spaces between the said electrical connection leads.
If the chip has, on its front face, an integrated optical sensor, the aforementioned encapsulating material is transparent.
In practice, such packages are produced at different points on a large leadframe which, at the end of the fabrication process, is cut up, in particular by a mechanical dicing means, so as to separate the packages.
However, it turns out that some of the packages obtained in this way cannot be used because of the appearance of cracks in the encapsulating material and flaking off of this material, in particular near the electrical connection leads, which result in the electrical connection leads becoming detached and the electrical connection wires fracturing or becoming unsoldered.
There is a need in the art to improve the quality of semiconductor packages with a visible leadframe.